Water-in-oil emulsions containing succinic esters



United States Patent 3,255,108 WATER-IN-OIL EMULSIONS CONTAINING SUCCINIC ESTERS Herbert F. Wiese, Cleveland, Ohio, assignor to The Lubrizol Corporation, Wicklii'fe, Ohio, a corporation of Ohio No Drawing. Filed May 14, 1963, Ser. No. 280,453 12 Claims. (Cl. 25232.7)

This application is a continuation-in-part of Serial No. 188,947, filed April 20, 1962, and now abandoned.

This invention relates to emulsions and in a more particular senses it relates to stable water-in-oil emulsions which are suitable for use as lubricants and hydraulic fluids.

Emulsions, especially water-in-oil emulsions, find use as lubricants and particularly as fire-resistant hydraulic fluids. To be effective for such use, emulsions must be stable under wide ranges of service conditions such as temperature and pressure. Preferably, they should be characterized also by non-corrosiveness, detergency, suitable frictional characteristics, anti-bacterial properties, and wear-reducing properties. Another important characteristic of emulsions, especially those to be used as hydraulic fluids, is fire-resistance. Thus, these lubricants find particular use in the die-casting industry and in the hydraulic systems of steam turbine plants, cotton gins, furnace charging devices in steel mills, and coal mining machinery. The requirement of these properties poses a diflicult problem in the formulation of emulsions which are economically feasible for commercial production.

Accordingly, it is an object of this invention to provide stable water-in-oil emulsions.

It is another object of this invention to provide emulsions suitable for use as lubricants and hydraulic fluids.

It is another object of this invention to provide emulsions which are suitable especially for use as fire-resistant hydraulic fluids.

These and other objects are accomplished in accordance with this invention by providing a stable water-in-oil emulsion suitable for use as a lubricant and a hydraulic fluid comprising from about 1 to 80 parts of water, from about 20 to 99 parts of mineral oil, and from about 0.2 to 10 parts of a succinic ester of a substantially saturated hydrocarbon-substituted succinic acid having at least about 50 aliphatic carbon atoms in the substituent and a polyhydric alcohol.

It will be noted that the succinic esters contemplated for use in the emulsions are characterized by the presence of a relatively large substituent on the succinic radical which contains at least about 50 aliphatic carbon atoms. The sources of this substituent include principally the high molecular weight petroleum fractions and olefin polymers, particularly polymers of mono-olefins having from 2 to about 30 carbon atoms. The especially useful polymers are the polymers of l-mono-olefins such as ethylene, propene, 1-butene,isobutene, l-hexene, l-octene, Z-methyl-l-heptene, 3-cyclohexyl-1-butene, and Z-methyl- 5-propyl-1-hexene. Polymers of medial olefins, i.e., olefins in which the olefinic linkage is not at the terminal position, likewise are useful. They are illustrated by 2- butene, B-pentene, and 4-oc'tene.

The polymers include also the interpolymers of the olefins such as those illustrated above with other interpolymerizable olefinic substances such as aromatic olefins, cyclic olefins, and polyolefins. The relative proportions of the mono-olefins to the other olefinic monomers in the interpolymers influence the stability and effectiveness of the succinimides derived therefrom in the emulsions of this invention. Thus, the interpolymers should be substantially aliphatic and substantially saturated, i.e., they should contain at least about 80%, preferably at least about 95%, on a Weight basis, of units derived from the aliphatic mono-olefins and no more than about 5% of unsaturated linkages based upon the total number of carbonto-carbon covalent linkages.

Examples of such interpolymers include copolymer of 95% (by weight) of isobutene with 5% of styrene; terpolymer of 98% of isobutene with 1% of piperylene and 1% of chloroprene; terpolymer of 95% of isobutene with 2% of l-butene and 3% of l-heXene; terpolymer of 60% of isobutene with 20% of l-pentene and 20% of l-octene; copolymer of 80% of l-hexene and 20% of l-heptene; terpolymer of 90% of isobutene with 2% of cyclohexene and 8% of propene; and copolymer of 80% of ethylene and 20% of propene.

Succinic esters in which the substituent is derived from an olefin polymer having a molecular weight of about 7505000 are preferred. Those from polymers of higher molecular Weight, i.e., from about 10,000 to about 100,000 or higher likewise are useful. 8

Another source of the substituent comprises petroleum fractions such as high molecular weight white oils and synthetic alkanes such as are obtained by hydrogenation of high molecular Weight olefins or fats.

The methods of preparing the polymers and interpolymers from which the succinic esters are derived are known. A particularly useful method comprises the treatment of an olefin (e.g., isobutene) or a mixture of olefins at a temperature from about '60 C. to about 20 C. in the presence of a Friedel-Crafts catalyst (e.g., boron trifluoride). The use of a solvent to facilitate mixing and the transfer of the heat of polymerization is advantageous. Solvents are exemplified by n-butane, isobutane, n-hexane, naphtha, carbon tetrachloride, and ethane.

The succinic esters contemplated for use in the emulappropriately substituted succinic acids or from compounds capable of yielding such succinic acids, the latter being illustrated by the acid anhydrides, halides, and esters of volatile alcohols or phenols, etc. These succinic acid-producing compounds can be prepared by e.g., the reaction of maleic anhydride with a high molecular weight olefin or a chlorinated hydrocarbon such as the olefin polymer described herein-above. The reaction involves merely heating the two reactants at a temperature preferably about 200 C. The product from such a reaction is an alkenyl succinic anhydride. The alkenyl group may be hydrogenated to an alkyl group. The anhydride may be hydrolyzed by treatment with water or steam to the corresponding acid.

In lieu of the olefins or chlorinated hydrocarbons, other hydrocarbons containing an activating polar substituent, i.e., a substituent which is capable of activating the hydrocarbon molecule in respect to reaction with maleic acid or anhydride, may be used in the aboveillustrated reaction for preparing the succinic acid-producing compounds. Such polar substituents are illustrated by sulfide, disulfide, nitro, mercaptan, bromine, ketone, or aldehyde radicals. Examples of such polarsubstitued hydrocarbons include propropylene sulfide, dipolyisobutene disulfide, nitrated mineral oil, di-polyethylene sulfide, brominated polyethylene, etc. Another method useful for preparing the succinic acids and their compounds involve the reaction of itaconic acid with an olefin or a polar-substituted hydrocarbon at a temperature usually within the range from about 100 C. to about 200 C.

The succinic acid halides can be prepared by the reaction of the acids or their anhydrides with a halogenation agent such as phosphorus tribromide, phosphorus penin-above. In most instances the esters derived from volatile alcohols or phenols are preferred.

The succinic acid esters of polyhydric alcohols are most conveniently prepared by the reaction of the succinic acid or anhydride with the alcohol under esterification conditions. An alternative method involves the transesterification of a succinic acid ester of a relatively volatile alcohol or phenol with the polyhydric alcohol. Both the esterification and the trans-esterification reactions are promoted by a small amount of a catalyst such as sodium methoxide, potassium hydroxide,- or sulfuric acid, although in most instances the reaction proceeds readily simply upon heating of the reactants.

The polyhydric alcohols are preferably those containing from 2 to 6 alcoholic radicals of which at least 1 is unsubstituted. The unsubstituted polyhydric alcohols include principally ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, erythritol, pentaerythritol, arabitol, adonital, xylitol, mannitol, sorbitol, neopentyl glycol, and pentaerythritol. Higher molecular weight polyhydric alcohols are also useful. Examples of such alcohols include the various polyethylene glycols, and polypropylene glycols.

Partially acylated polyhydric alcohols likewise are contemplated for use herein. The partially acylated poly-' hydric alcohols are preferably those containing from 2 to 6 alcoholic radicals of which at least one but not all are acylated with an aliphatic carboxylic acid having from about 8 to about 30 carbon atoms. Examples are glycerol mono-oleate, glycerol distearate, sorbitan mono- The polyhydric alcohols may also contain ether link ages within their molecular structure. The ether-containing polyhydric alcohols may be obtained by dehydrating a polyhydric alcohol. Examples of such derivatives are sorbitan and mannitan. -The ether-containing polyhydric alcohols may also be obtained by reacting a polyhydric alcohol with an epoxide. The epoxides are for the most part hydrocarbon epoxides and substantially hydrocarbon epoxides. The hydrocarbon epoxide may be an alkylene oxide or an aryl-alkylene oxide. The arylalkylene oxides are exemplified by styrene oxide,.paraethylstyrene oxide and para-chlorostyrene oxide. The alkylene oxides include principally the lower alkylene oxides such as ethylene oxide, propylene oxide, 1,2-butene oxide and 1,2-hexene oxide. The substantially hydrocarbon epoxides may contain polar substituents. The polar substituent is usually a halo radical such as chloro, fluoro, bromo, or iodo; an ether radical such as methoxy or phenoxy; or an ester radical such as carbomethoxy. Examples of such epoxides are epichlorohydrin and butyl 9,10-epoxy-stearate. The number of ether linkages in the product is determined by the amount of epoxide added. Thus it is possible to react a polyhydric alcohol such as sorbitol with 1, 2, 3, or more equivalents of anepoxide such as propylene oxide.

The polyhydric alcohols contemplated for use in this invention may also be ether-containing acylated polyhydric alcohol. These may be prepared by a number of methods. A polyhydric alcohol may be dehydrated and subsequently acylated or an alcoholic radical may be acylated first followed by dehydration of other alcoholic radicals. As mentioned previously, the ether linkage may also be introduced by the reaction of an epoxide with the polyhydric alcohol either before or after acylation. Examples of ether-containing acylatedpolyhydric alcohols include polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tri-stearate, polyoxyethylene glycerol di-stearate, polyoxypropylene sorbitan di-linoleate, and polyoxypropylene pentaerythritol monooleate.

The reaction of a succinic acid-producing compound with the above-illustrated polyhydric alcohols is generally carried out at a temperature of at least C., preferably above C. The use of a solvent such as benzene,

toluene, naphtha, mineral oil, xylene, n-hexane, or the like is often desirable in the above reaction to facilitate the control of the reaction temperature.

The relative proportions of the succinic acid-producing reactant and of the polyhydric alcohol reactant usually are such that at least about one-tenth and preferably onehalf of a stoichiometrically equivalent amount of the alcohol reactant is used for-each equivalent of the acidproducing reactant. In this regard it will be noted that the equivalent weight of the polyhydric alcohols is based on the number of unsubstituted hydroxy radicals in the molecular structure. Thus, ethylene glycol has two equivalents per mole; pentaerythritol has 4 equivalents per mole; and sorbitan monooleate has 3 equivalents per mole. The number of equivalents per mole of epoxide treated polyhydric alcohols is determined analytically.

The succinic esters likewise can be obtained from succinic acid halides or other succinic acid-producing compounds. For example, the sorbitan mono-oleate ester is formed by heating a mixture of sorbitan monooleate with the dihalide of an appropriately substituted succinic acid.

The following examples illustrate the methods for preparing the succinic esters useful in the emulsions of this invention: (parts are by Weight unless otherwise indicated).

Example A A polyisobutenyl succinic anhydride is prepared by the reaction of a chlorinated polyisobu-tene with maleic anhydride at 200 C. The chlorinated polyisobutene is prepared by blowing chlorine gas through polyisobutene having an average molecular weight of 1000 at a temperature of 104-110 C. until the chlorine content reaches 4.3%. The resulting alkenyl succinic anhydride is found to have a saponification number of 109 (corresponding to an equivalent weight of 514). To 770 parts (1.5 equivalents) of this polyisobutenyl succinic anhydride there is added 126 parts (1.5 equivalents) of a commercial mix ture of polyol fatty acid esters predominantly sorbitan monooleate, 588 parts of mineral oil, 9 parts of par-atoluene sulfonic acid monohydrate and 500 parts (by volume) of xylene. The mixture is heated to reflux at C. and is held at this temperature for 12 hours to remove water. The reaction mixture is then washed with Water and dried by heating to C./20 mm. The residue is found to have a saponification number of 68.

Example B Example C The procedure of Example A is repeated except that the sorbitan monooleate is replaced with 1 equivalent of a commercial mixture of polyol fatty acid esters predominantly sorbitan tristearate.

Example D The procedure of Example A is repeated except that the sorbitan monooleate is replaced with 1 equivalent of a commercial mixture of ethylene oxide treated polyol fatty acid esters which is predominantly polyoxyethylene sorbitan tri-stearate.

Example E A polyisobutenyl succinic anhydride having an equivalent weight of 518 is prepared according to the procedure of Example A. To a mixture of 518 parts (1 equivalent) of this polyisobutenyl succinic anhydride there is added 200 parts (1 equivalent) of commercial polyethylene glycol, 7.2 parts of para-toluene sulfonic acid monohydrate, and 400 parts of xylene. The mixture is heated at 140-150 C. for hours while water is removed. The volatile components are then removed by heating to 105 C./4 mm. and 471 parts of mineral oil is added and the product filtered to remove solid impurities. The filtrate is found to have a saponification number of 50.

Example F To a mixture of 300 parts (0.545 equivalent) of a polyisobutenyl succinic anhydride prepared as in Example A there is added 279 parts (0.545 equivalent) of commercial polypropylene glycol, 3 82 parts of mineral oil, and 28.5 parts of an acid activated blea'chirrg earth. The mixture is heated to 150 C. and purged with nitrogen for 20 hours at this temperature. The mixture is filtered while hot and I the filtrate is found to have a saponification number of 35.

Example G A mixture of 600 parts (1.09 equivalents) of a polyisobutenyl succinic anhydride prepared as in Example A, 232 parts (1.09 equivalents) of a commercial polypropylene glycol, 547 parts of mineral oil, and parts of acid activated bleaching earth is heated to 115 G. The mixture is purged with nitrogen and heated to 150-1 C. for 17 hours and 200 C. for 4 hours. The mixture is filtered and 43.2 parts (0.745 equivalent) of propylene oxide is added to the cooled filtrate. This mixture is heated at 85-90 C. for 16 hours whereupon the temperature of the mixture is maintained at 85 C. while reducing to 80 mm. of pressure. The residue is the product and is found to have a saponification number of 48.

Example H A mixture of 3,318 parts (3 moles) of a polyisobutenyl succinic anhydride prepared as in Example A and having a saponification number of 101, 408 parts (3 moles) of pentaerythritol, and 2,445 parts of mineral oil is heated to 150 C. for 5 hours. The mixture is then heated to '200210 C. for 5 hours and filtered. The filtrate is the product and is found to have a saponificationnumber of 50.

Example I Example I A mixture of 895 parts (1.6 equivalents) of a poly-isobutenyl succinic anhydride prepared as in Example A and having a saponification number of 100, 181 parts (0.744 equivalent) of the polyoxyethylene sonbitan monooleate mixture of Example B, and 714 parts of mineral oil is heated to 150 C. in 4 hours. The mixture is then purged with nitrogen for 7 hours at this temperature. Ten parts of a filter aid is added and the mixture filtered while hot. The filtrate is the product and is found to have a saponification number of 54.

Example K A mixture of 544 parts (1 equivalent) of a polyisobutenyl succinic anhydride prepared as in Example A and having a saponifilcation number of 103, 358 parts (4 equivalents) of the sorbitan monoleate mixture of Example A, and 594 parts of mineral oil is heated to 150 C. in one hour. The mixture is held at this temperature for 3 hours While [being purged with nitrogen. The mixture is filtered while hot, and the filtrate is found to have a saponification number of 76.

Example L Sodium (0.5 parts) is dissolved in 60.8 parts (2 equivalents) of melted sorbito'l while stirring in an atmosphere of nitrogen, and 348.6 parts (6 equivalents) of propylene oxide is added over a period of 20 hours at a temperature of l50-210 C. The mixture is heated an additional hour at 175 C. giving the product which is found to have a hydroxyl content of 9.26%.

A mixture of 358 grams (2 equivalents) of this propylene oxide treated sonbitol, 272 grams (0.5 equivalent) of a polyisobutenyl succinic anhydride prepared as in Example A and having a saponification number of 103, and 418 parts of mineral toil is heated to 150 C. and purged with nitrogen at this temperature for 3.5 hours. The 'hot solution is filtered and the filtrate is found to have a saponification number of 25.

Example M Sodium (0.5 part) is dissolved in 60.8 parts (2 equivof melted sorbitol in a nitrogen atmosphere and the mixture is stirred for 0.5 hour. Propylene oxide (348.6 parts, 6 equivalents) is added to the mixture over a period of 20 hours at a temperature of ISO-200 C. This mixture is heated an additional hour at -140 C. to give the product which has a hydroxyl content of 16.2%.

A mixture of 210 parts (2 equivalents) of this propylene oxide treated sorbitol, 272 parts (0.5 equivalent) of a polyisobutenyl succinic anhydride prepared as in Example A and having a sa-ponification number of 103, and 31 8 parts of mineral oil is heated to C. The reaction temperature is then raised to 150 C. while purging with nitrogen, and the mixture is maintained at this temperature for 3.5 hours. The mixture is filtered and the filtrate is found to have a saponification number of 36.

Example N A mixture of 555 parts (1 equivalent) of a polyisobutenyl succinic anhydride prepared according to the procedure of Example A and 45 parts (1 equivalent) of 1,4- butane diol is heated to C. The mixture is maintained at a temperature of 135-190 C. for 11 hours while removing the water as it is formed. Fifty parts of a filter aid and 250 parts of mineral oil are added to the warm mixture which is then filtered. The filtrate is the product and is found to have a saponification number of 68.

Example P A mixture of 544 parts (1 equivalent) of a polyisobutenyl succinic anhydride prepared according to the pro- 7 cedure of Example A, 90.6 parts (3 equivalents) of mannitol, and 417 parts of mineral oil is heated to 200 C. The mixture is purged with nitrogen while heating at 200 210 C. for 3.5 hours. The mixture is filtered while hot and the filtrate is found to have a saponification number The oil of the emulsion may he a hydrocarbon oil having viscosity values from 50 SUS (Saybolt Universal seconds) at 100 F. to 200 SUS at 210 F. Mineral oils having lubricating viscosities (e.g., SAE 5-90 grade oils) are especially advantageous for use in the emulsion. A mixture of oils of different sources likewise in useful. Such a mixture is available from mineral oils, vegetable oils, animal oils, synthetic oils of the silicon type, synthetic oils of the polyolefin type, synthetic oils of the polyester type, etc.

The emulsions of this invention contain from 1 to 80 parts of water and [from to 99 parts of oil. (All parts in this specification and claims are expressed in terms of weight unless otherwise indicated.) However, emulsions having the most desirable properties are composed of from to parts of water and 50 to 70 parts of oil. Also, emulsions intended for use as fire-resistant hydraulic fluids should contain at least about 30% of water. The concentration of the succinic ester in the emulsions is from 0.2 to 10 parts, more often from 1 to 5 parts, per

100 parts of the emulsion. The principal function of the succinic ester is that of an emulsifier, although it also impart-s detergency to the emulsion.

The emulsions can be prepared simply by mixing with water, oil, the succinic ester, and any other ingredient which may be desirable, in a homogenizer or any other efiicient blending device. Heating the emulsion during or after it is prepared is not necessary. The order of mixing of the ingredients is not critical, although it is convenient first to prepare an oil concentrate containing from about 50 to 95 parts of the oil-soluble ingredients and from about 5 to 50 parts of oil and then to emulsify the concentrate with water in appropriate proportions.

Although the emulsions described hereinbefore are, in themselves, useful, they nevertheless are susceptible to improvement by the incorporation of chemical additives which impart properties desired {or various specific applications. One such additive is an emulsion stabilizer which functions to improve the stability of the emulsion against deterioration due to temperature, pressure, oxidation of the oil, and other harmful environments. Stabilizers include phosphatides, especially those having the structural formula wherein G is selected from the class consisting of fatty acyl radicals and phosphorus-containing radicals having the structural grouping .for the most part those derived from fatty acids having .from 8 to 30 carbon atoms in the fatty radicals such as .a mono-aryl ether of an aliphatic glycol.

octanoic acid, stearic acid, oleic acid, palmitic acid, behenic acid, myristic acid, and oleostearic acid; Especially desirable radicals are those derived from commercial tatty compounds such as soyabean oil, cotton seed oil, and castor seed oil. A particularly effective phosphatide is soyabean lecithin which is described in detail in Encyclopedia of Chemical Technology, Kirk and Othmer, volume 8, pages 309-326 (1952). v

The emulsion stabilizer may be an aliphatic glycol or The aliphatic glycol may be a polyalkylene glycol. -It is preferably one in which the alkylene radical is a lower alkylene radical having from 1 to 10 carbon atoms. Thus, the aliphatic glycol is illustrated by ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, 1,2-butylene glycol, 2,3-bu-tylene glycol, tetraethylene glycol, hexamethylene glycol, or the like. Specific examples of the ethers include monop-henyl ether of ethylene glycol, mono-(heptylphenyl) ether of triethylene glycol, mono-(alpha-octylbeta-naphthyl) ether of tetra propylene glycol, mono- (polyisobutene(molecular weight of l000)-substituted phenyl) ether of octapropylene .glycol, and mono-(o,p-dibutylphenyl) ether of polybutylene glycol, mono-(heptylphenyl) ether of trimethylene glycol and mono-(3,5-dioctylphenyl) ether of tetra-trimethylene glycol, etc. The mono-aryl ethers are obtained by the condensation of a phenolic compound such as an alkylated phenol or naphthyl with one or more moles of an epoxide such as ethylene oxide, propylene oxide, trimethylene oxide, or 2,3-hexylene oxide. The condensation is promoted by a basic catalyst such as an alkali or alkaline earth metal hydroxide, alcoholate, or phenate. The temperature'at which the condensation is carried out may be varied within wide ranges such as from room temperature to about 250 C. Ordinarily it is preferably 50-150 C. More than one mole of the epoxide may condense with the phenolic compound so that the product may contain in its molecular structure one or more of the radicals derived from the epoxide. A polar-substituted alkylene oxide such as epichlorohydrin or epibromohydrin likewise is useful to prepare the mono-aryl ether product and such product likewise is useful as the emulsion stabilizer in this invention.

Likewise useful as the emulsion stabilizers are the monoalkyl ethers of the aliphatic 'glycols in which the alkyl radical is, e.g., octyl, nonyl, dodecyl, behenyl, etc. The fatty acid esters of the mono-aryl or monoalkyl ethers of aliphatic glycols also are useful. The fatty acids include, e.g., acetic acid, formic acid, butanoic acid, hexanoic acid, oleic acid, stearic acid, behenic acid, decanoic acid, isostearic acid, linolenic acid, as well as commercial acid mixtures such as are obtained by the hydrolysis of tall oils, sperm oils, etc. Specific examples are the oleate of mono- (hepty-lphenyl) ether of tetraethylene glycol and acetate of mono-(polypropene (having molecular weight of 1000)- substituted phenyl) ether of tri-propylene glycol.

The alkali metal and ammonium salts of sulfonic acids likewise are emulsion stabilizers. The acids are illustrated by decylbenzene sulfonic acid, di-dodecylbenzene sulfonic acid, mahogany sulfonic acid, heptylbenzene sulfonic acid, polyisobutene sulfonic acid (molecular weight of 750), and decylnaphthalene sulfonic acid, and tri-decylbenzene sulfonic acid. The salts are illustrated by the sodium, potassium, or ammonium salts of the above acids.

Only a small amount of the stabilizer is necessary for the purpose. It may be as little as 0.01 part and seldom exceeds 2 parts per parts of the emulsion. In most instances it is within the range from 0.1 to 1 part per 100 parts of the emulsion.

Another additive which finds use in the emulsion is an extreme pressure agent, i.e., one which improves the loadcarrying properties of the emulsion. lead or nickel or a Group II metal phosphorodithioate in which the metal may be magnesium, calcium, barium, strontium, zinc, or cadmium. Zinc is an especially pre- It is illustrated by a ferred metal. Specific examples of the metal phosphorodi-thioates include Zinc di(4-methyl-2-pentyl)phosphorodithioate,

Zinc O-methyl-O'-dodecylphosphorodithioate,

Barium diheptylphosphorodithioate,

Barium di (n-butylphenyl) phosphorodithioate,

Magnesium di-cyclohexylphosphorodithioate,

Cadmium salt of an equal molar mixture of dimethylphosphorodi-thioic acid and di-octylphosphorodithioic acid,

Zinc di-n-nonylphosphorodithioate,

Zinc di-dodecylphosphorodithioate,

Lead di-pentylphosphorodithioate,

Nickel di-octylphosphorodithioate, and

Zinc di-(heptylphenyl)phosphorodithioate.

Methods for preparing the phosphorodithioic acids are known in the art including, for example, the reaction of an alcohol or a phenol with phosphorus pentasulfide. Likewise known are the methods for preparing the Group II metal salts of phosphorodithioic acids. Such methods are illustrated by the neutralization of phosphorodithioic acids or mixtures of such acids with zinc oxide.

Other extreme pressure agents useful in the emulsions of this invention include the chlorinated waxes; sulfurized or phosphosulfurized fatty acid esters; diand tri-hydrocarbon p-hosphites and phosphates; di-hydrocarbon polysulfides; and metal dithiocarbamates. The chlorinated waxes are exemplified by chlorinated eicosane having a chlorine content of 50% or other chlorinated petroleum waxes having a chlorine content of 5 %60%. The sulfurized fatty esters are obtained by the treatment of a lower alkyl ester of a fatty acid having at least about 12 carbon atoms with a sulfurizing agent such as sulfur, sulfur mono-chloride, sulfur dichloride, or the like. The fatty acid esters are illustrated by methyl oleate, methyl stearate, isopropyl myristate, cyclohexyl ester of tall oil acid, ethyl palmitate, isooctyl laurate, diester of ethylene glycol with stearic acid, etc. Commercial mixtures of esters likewise are useful. They include, for example, sperm oil, Menhaden oil, glycerol trioleate, etc. The sulfurization is effected'most conveniently at temperatures between 100 C. and 250 C. -More than one atom of sulfur can be incorporated into the ester and for the purpose of this invention sulfurized esters having as many as four or five atoms of sulfur per molecule have been found to be useful. Examples include sulfurized sperm oil having a sulfur content of 5%, sulfurized tall oil having a sulfur content of 9%, sulfurized methyl oleate having a sulfur content of 3%, and sulfurized stearyl stearate hav ing a sulfur content of 15%.

The phosphosulfurized fatty acid esters are obtained by the treatment of the esters illustrated above with a phosphorus sulfide such as phosphorus pentasulfide, phosphorus sesquisulfide, or phosphorus heptasulfide. The treatment is illustrated by mixing an ester with from about 0.5% to 25% of a phosphorus sulfide at a temperature within the range from about 100 C. to 250 C. The lproducts contain both phosphorus and sulfur but the precise chemical structure of such products is not clearly understood.

The phosphites and phosphates useful herein are the diand t-ri-esters Olf phosphorus or phosphoric acid in which the ester radical is derived from a substantially hydrocarbon radical including aryl, alkyl, alkaryl, arylalkyl, or cycloalkyl radical as well as a hydrocarbon radical having a polar substituent such as chloro, nitro, bromo, ether, or the like. Particularly desirable phosphites and phosphates are those :in which the ester redicals are phenyl, alkyl-phenyl radicals or alkyl radicals containing from 6 to 30 carbon atoms. Examples are: dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, di- (pentyl-phenyl phosphite, bisdipentylphenyl) phosphite, tridecyl phosphite, di-stearyl phosphite, dimethyl naphthyl phosphite, oleyl 4-pentylphenyl phosphite, triphenyl phos- 10 phite, bi s(hexapropylene-substituted phenyl)phosphite, tri (n chloro-3-heptylphenyl)phosphite, triphenyl phosphate, tricresyl phosphate, tri(p-chlorophenyl)phosphate, and tri hep tylphenyl phosphate.

The metal dithiocarbamates include principally thoseof zinc, lead, strontium, nickel, cadmium, and palladium with N,N-dialkyldithiocarbamic acids in which the alkyl radical contains from 3 to about 30 carbon atoms. Examples are zinc N,N- dioctyl dithiocarbarnate, lead N,N- dicyclohexyl dithiocarbamate, cadmium N,N-dibehenyl dithiocarbamate, lead N,N-didodecyl dithiocarbamate, and mixtures thereof.

The concentration of the extreme pressure agent is usually within the range from about 0.05 to about 5 parts, although it is seldom necessary to employ more than 2 parts of this agent per 100 parts of the emulsion.

Another type of additive which finds use in the emulsion is a rust-inhibiting agent. The most effective rustinhibiting agents in the emulsions of this invention are aliphatic amines, especially aliphatic primary amines having at least about 8 carbon atoms in the molecule. The aliphatic amines are preferably tertiary-alkyl primary amines having from about 12 to about 30 carbon atoms. The amines include stearyl amine, oleyl amine, myristyl amine, pal-mityl amine, n-octyl amine, dodecyl amine, octadecyl amine, and other commercial primary amine mixtures such as the mixture in which the aliphatic radical is a mixture of tertiary-alkyl radical having from ll to 14 carbon atoms and an average of 12 carbon atoms, and the mixture in which the aliphatic radical is a mixture of tertiary-alkyl radicals having from 18 to 24 carbon atoms.

Also effective as rust-inhibiting agents are the salts of an aromatic acid such. as benzoic acid, toluic acid, naphthoic acid, o-phthalic acid, or p-phthalic acid with any of the aliphatic amines listed above. Salts derived from other acids such as p-aminobenzoic acid and ochflorobenzoic acid like-wise are useful.

The salts of amines with the aromatic acids are prepared simply by mixing the reactants at a temperature below the dehydration temperature, i.e., below C. In most instances the reaction is exothermic and heating is not necessary, A solvent such as benzene,-toluene, naphtha, or chlorobenzene may be used.

Still another class of rust-inhibiting agents are the hydroxy-alkyl amines, especially the long chain (i.e., C aliphatic amines containing one or tWo hydroxyalkyl substituents on the amine nitrogen atom. Examples are N-(Z-hydroxyethyl)octylamine, N,N-di-(2-hydroxy-1- pro pyl) dodecyl'amine', N- 3 -hydr0xy-l -pentyl octadecylamine, and N,N-di-(2-hydroxy3-butyl)decylamine.

Also useful as the rust-inhibiting agents are the nitrous acid salts of the long chain aliphatic amines illustrated above. Such salts are obtained simply by mixing at ordinary temperatures such as room temperature an amine with nitrous acid. Specific examples include the nitrous acid salt of the tertiary-alkyl ((1 primary amine and the nitrous acid salt of octadecylamine.

The concentration of rust-inhibiting agent in the emulsion depends to some extent upon the relative concentration of water in the emulsion. Ordinarily from about 0.01 part to about 2 parts of a rust--inhibiting agent per parts of the emulsion is sutficient.

Still another type of additive which finds use in these Example 1.Emulsin Parts by weight The product of Example A 9.0 Soyabean lecithin 1.8 A tertiary-alkyl primary amine having a molecular weight of 191 in which the tertiary-alkyl radical is a mixture of radicals having from 11 to 14 carbon atoms 0.6 Zinc di-isooctyl phosphorodithioate 3.0 SAE 30 mineral lubricating oil 285.6 Silicone anti-foam agent 0.0075 Water .200

, Example 2.C0n:centrate The product of Example B 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc diisooctyl phosphorodithioate 3.0 SAE 40 mineral lubricating oil 285.6 Silicone anti-foam agent 0.0045

Example 3.Emalsi0n The product of Example E 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine-0f Example 1 0.6 Zinc diisooctyl phosphorodithioate 3.0 SAE 40 mineral lubricating oil 285.6 Silicone anti-lfoam agent 0.0075 Water 200 Example 4 .-Emulsi0n Parts by weight The product of Example I 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc di-(heptylphenyl)phosphorodithioate 2.0 SAE 40 mineral lubricating oil 287.1 Silicone anti-foam agent 0.0075 Water 200 Example 5 .Emulsi0n The product of Example I 9.0 Soyabean lecithin 1.8 A tertiary-alkyl primary amine having a molecular Weight of 330 in which the tertiary alkyl radical is a mixture of radicals having from 11 to 14 carbon atoms 0.6 Zinc diisooctyl phosphorodithioate 3.0 SAE 40 mineral lubricating oil 285.6 Silicone anti-foam agent 0.0075 Water 200 Example 6.-Emulsi0n The product of Example I 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc di-(heptylphenyl)phosphorodithiate 1.5 Zinc diisooctyl phosphorodithioate 1.5 SAE 40 mineral lubricating oil 285.6 Silicone anti-foam agent 0.0075 Water 200 12 I Example 7.--Emulsion The product of Example D 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 5 0.6 Zinc di-(heptylphenyl)phosphorodithioate 3.0 An amine mixture consisting of, by weight, 91% oleamide, 6% stearamide, and 3% linoleamide 0.6 SAE 40 mineral lubricating oil 285.0 Silicone anti-foam agent 0.0075 Water 200 Example 8.C0ncentrate The product of Example I 54.9 Soyabean lecithin 11.0 The tertiary-alkyl primary amine of Example 1 3.7 Zinc di-isooctyl phosphorodithioate 18.3 SAE 40 mineral lubricating oil 12.1 Silicone anti-foam agent 0.028

Example 9.C0ncentrate The product of Example E 9.0 Soyabean lecithin 1.8 The benzoic acid salt of the tertiary-alkyl primary amine of Example 1 0.6 Lead diamyl dithiocarbamate 3.0 Sulfurized sperm oil having a sulfur content of 10% 3.0 SAE 20 mineral lubricating oil 282.6 Silicone anti-foam agent a- 0.0045

Example 10.-Emulsi0n The product of Example H 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc di-(heptylphenyl)phosphorodithioate 3.7 SAE 40 mineral lubricating oil 284.9 Silicone anti-foam agent 0.0045 Water 200 Example 11.-Emulsi0n The product of Example F 18.0 Soyabean lecithin 3.6 The nitrous acid salt of the tertiaryalkyl primary amine of Example 1 1.2 Sulfurized sperm oil having a sulfur content of 10% 18.0 4-methyl 2,6-di-tertiary butylphenol 3.0 SAE 5 mineral lubricating oil 536.2 Silicone anti-foam agent 0.015 Water 400.0

Example 12.-Emalsion The product of Example C 30 SAE 20 mineral lubricating oil 570 Water 400 Example 13.-Emulsion The product of Example 12 49.5

Example 16.-Emulsin The product of Example L 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc di-(heptylphenyl)phosphorodithioate 3.75 SAE 40 mineral lubricating oil 274.8 Silicone anti-foam agent 0.0075 Water 200 Example 17.Emulsi0n The product of Example M 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc di- (heptylphenyl phosphorodithioate 3 .75 SAE 40 mineral lubricating oil 271.8 Silicone anti-foam agent 0.0075 Water 200 Example 1 8.Emuls i0n Parts by weight The product of Example I 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Dipentene disulfide having a sulfur content of 36% 6.0 SAE 40 mineral lubricating oil 282.6 Silicone anti-foam agent 0.0075 Water 200 Example 19.-C0ncentrate The product of Example I 9.0 The mono-(heptylphenyl)ether of tetraethylene glycol 1.8 The tertiary-alkyl primary amine of Example 1 0.6 Zinc di-(heptylphenyl)phosphorodithioate 1.5 Zinc diamyl dithiocarbamate 1.5 SAE 20 mineral lubricating oil 285.6 Silicone anti-foam agent 0.0045

Example 20.Emulsi0n The product of Example I 9.0 The tertiary-alkyl primary amine of Example 1 0.6 Zinc diisooctyl phosphorodithioate 3.0 SAE 40 mineral lubricating oil 287.2 Silicone anti-foam agent 0.0075 Water 200 Example 21.Emulsi0n The concentrate of Example 8 36 SAE 40 mineral lubricating oil 564 Water 400 Example Z2.Emulsi0n The product of Example 21 970 Ethylene glycol 30 Example 23.C0ncentrate The product of Example I 9.0 Soyabean lecithin 1.8 The tertiary-alkyl primary amine of Example 0.6 SAE 40 mineral lubricating oil 100 Example 24f-Emulsi0n The product of Example 23 100 SAE 40 mineral lubricating oil 200 Silicone anti-foam agent 0.007 Water 200 As indicated previously the emulsions of this invention are useful as lubricants as well as hydraulic fluids, especially fire-resistant hydraulic fluids for use in mining, die-casting and injection molding, welding equipment, etc. A specific illustration of such utility is as follows: an emulsion prepared from a mixture consisting of 95 parts (by weight) of an SAE 20 miner-a1 lubricating oil, 2 parts of the polyisobutene-substituted succinic ester 14 of Example I and 5 parts of Water is useful as the powertransrnitting fluid in a hydraulic pump.

Other advantages of the emulsions of this invention include, for example, thermal stability, wear-reducing properties, fire-resistance, rust-inhibiting properties, and anti-bacterial properties. Thus, for instance, the emulsion of Example 10 is found to pass the Heat Stability Test, in which a 50-cc. sample of the emulsion in a container is immersed in boiling water. (The emulsion is said to pass the test if no appreciable amount of water separates from the emulsion at the end of one hour of heating.) 4

The lubricating properties, especially thewear-reducing properties, of the emulsion of this invention are shown by the results of a proposed ASTM wear test. In the test, the emulsion is placed in a hydraulic pump (in this particular test, Viclcers 104E Vane Pump) Which is operated under the following conditions: motor speed, 1200 rpm; approximate fluid flow rate, 8 gallons per minute; pressure, 1000 p.s.i.; and sump temperature, 150 F. The results of the test are shown in Table I. A commercial emulsion hydraulic fluid is also evaluated for the purpose of comparison.

The fire-resistance of the emulsions of this invention is shown by the fact that the emulsion prepared according to Example 21 is found to pass the fire-resistance test for hydraulic fluids as required by the Bureau of Mines of the US. Government (test procedure described in Federal Register, December 17, 1959, Volume 24, number 245, title 30, part 35, and sections 35.1-35.23).

The rust-inhibiting properties of the emulsions of this invention are shown by the results of a rust test in which one-half of a steel strip is immersed in a 50 cc. sample of the emulsion. At the end of five Weeks, the strip is inspected for rust. The results are summarized in Table 11.

TABLE II Rust Result Emulsion Tested Portion of Strip Portion of Strip Immersed in Exposed to Fluid (for purpose of comparison).

A portion of the unclaimed subject matter disclosed herein is disclosed and claimed in co-pending application Ser. No. 274,905 filed April 23, 1963.

A portion of the unclaimed subject matter disclosed herein and relating to the succinic esters of hydrocarbonsubstituted succinic acids having at least about 50 aliphatic carbon atoms in the substituent and a polyhydric alcohol is disclosed and claimed in co-pending application Ser. No. 274,905, filed April 23, 1963.

What is claimed is:

11. A stable water-in-oil emulsion suitable for use as a lubricant and a hydraulic fluid comprising from about 1 to parts of water, from about 20 to 99 parts of mineral oil, and from about 0.2 to 10 parts of a succinic ester of a hydrocarbon-substituted succinic acid having at least about 50 aliphatic carbon atoms in the substituent and a polyhydric alcohol having from 2 to 6 alcoholic radicals of which at least one is unsubstituted.

2. The emulsion of claim 1 characterized further in that it contaiins from about 0.05 to 5 parts of a zinc phosphorodithioate.

3. The emulsion of claim 1 characterized further in that it contains from about 0.1 to about 5 parts of an aliphatic primary amine in which the aliphatic radical is a tertiary alkyl radical having from 8 to 30 carbon atoms.

4. The emulsion of claim 1 characterized further in that it contains from about 0.01 to about 5 parts of a phosphatide.

5. A stable Water-in-oil emulsion suitable for use as a lubricant and a hydraulic fluid comprising from about 1 to 80 parts of water, from about 20 to 99 parts of mineral oil, from about 0.2 to parts of a succinic ester of a hydrocarbon-substituted succinic acid having at least about 50 aliphatic carbon atoms in the substituent and a polyhydric alcohol having from 2 to 6 alcoholic radicals of which at least one is unsubstituted, from about 0.1 to 5 parts of an aliphatic primary amine in which the aliphatic radical is a tertiary alkyl radical having from 8 to 30 carbon atoms, and from about 0.01 to 5 parts of a phosphatide.

6. The emulsion of claim Scharacterized further in that it contains from about 0.05 to about 5 parts of a zinc phosphorodithioate.

7. A stable 'water-in-oil emulsion suitable for use as a lubricant and a hydraulic fluid comprising from about 20 to 50 parts of water, from about 50 to 80 parts of a mineral oil, and from about 1 to 5 parts of a succinic ester of a hydrocarbon-substituted sucinic acid having at least about 50 aliphatic carbon atoms in the substituent and a partially acylated polyhydric alcohol having from 2 to 6 alcoholic radicals of which at least one is unsubstituted.

8. A stable water-in-mineral oil emulsion suitable for use as a lubricant and a hydraulic fluid comprising from about 20 to 50 parts of water, from about 50 to 80 parts of a mineral oil, and from about 1 to 5 parts of a succinc ester of a hydrocarbon-substituted succinic acid having at least about 50 aliphatic carbon atoms in the substituent and at least about 0.1 equivalent of polyoxyethylene sorbitan monooleate.

9. The emulsion of claim 8 characterized further in that it contains from about 0.1 to 3 parts of a tertiary-alkyl primary amine having from about 8 to 30 carbon atoms in the alkyl radical, and from about 0.1 to about 3 parts of a phosphatide.

10. The emulsion of claim 9 characterized further in that it contains'from about 0.1 to 2 parts of a zinc phosphorodithioate.

11. A stable 'water-in-mineral oil emulsion suitable for use as a lubricant in a hydraulic fluid comprising from about 20 to parts of water, from about 50 to parts of a mineral oil, from about 1 to 5 parts of a succinic ester of a hydrocarbon-substituted succinic acid having at least about 50 aliphatic carbon atoms in the substituent and about 0.5 equivalent of polyoxyethylene sorbitan monooleate, from about 0.1 to 2 parts of zinc di-(heptylphenyl)phosphorodithioate, from about 0.1 to 1 part of a tertiary-alkyl primary amine having a molecular weight of 191 in which the tertiary-alkyl radical is a mixture of radicals having from 11 to 14 carbon atoms, and from about 0.1 to 3 parts of soyabean lecithin.

12. A stable water-in-mineral oil emulsion suitable for use as a lubricant in a hydraulic fluid comprising from about 20 to 50 parts of water, from about 50 to 80 parts of a mineral oil, from about 1 to 5 parts of a succinic ester of a hydrocarbon-substituted succinic acid having at least about 50 aliphatic carbon atoms in the substituent and about 0.5 equivalent of polyoxyethylene sorbitan monooleate, from about 0.1 to 2 parts of zinc diisooctyl phosphorodithioate, from about 0.1 to 1 part of a tertiaryalkyl primary amine having a molecular weight of 191 in which the tertiary-alkyl radical is a mixture of radicals having from 11 to 14 carbon atoms, and from about 0.1 0t 3 parts of soyabean lecithin.

References Cited by the Examiner UNITED STATES PATENTS Ashburn et al. 25249.9

L. G. XIARHOS, Assistant Examiner. 

5. A STABLE WATER-IN-OIL EMULSION SUITABLE FOR USE AS A LUBRICANT AND A HYDRAULIC FLUID COMPRISING FROM ABOUT 1 TO 80 PARTS OF WATER, FROM ABOUT 20 TO 99 PARTS OF MINERAL OIL, FROM ABOUT 0.2 TO 10 PARTS OF A SUCCINIC ESTER OF A HYDROCARBON-SUBSTITUTED SUCCINIC ACID HAVING AT LEAST ABOUT 50 ALIPHATIC CARBON ATOMS IN THE SUBSTITUENT AND POLYHYDRIC ALCOHOL HAVING FROM 2 TO 6 ALCOHOLIC RADICALS OF WHICH AT LEAST ONE IS UNSUBSTITUTED, FROM ABOUT 0.1 TO 5 PARTS OF AN ALIPHATIC PRIMARY AMINE IN WHICH THE ALIPHATIC RADICAL IS A TERTIARY ALKYL RADICAL HAVING FROM 8 TO 30 CARBON ATOMS, AND FROM ABOUT 0.01 TO 5 PARTS OF A PHOSPHATIDE.
 6. THE EMULSION OF CLAIM 5 CHARACTERIZED FURTHER IN THAT IT CONTAINS FROM ABOUT 0.05 TO ABOUT 5 PARTS OF A ZINC PHOSPHORODITHIOATE. 